Study On Formation And Magnetic Properties Of Boron-rich FeSiBCuNbNi(Co) Amorphous Alloy

In the field of power electronics,some magnetic core components such as transformers for meter measurement and filters for power transmissions require a good linear relationship in the hysteresis loop.The high cost of cobalt-based amorphous alloys and permalloys with low magnetic permeability and good hysteresis loop linearity greatly limits their application scale.Therefore,the development of relatively cheap iron-based amorphous/nanocrystalline alloys is of great significance.In this thesis,the mother alloy ingot was prepared by arc melting furnace,and the strip was prepared by single roll rapid quenching method.The thermal stability,phase analysis before and after heat treatment and soft magnetic properties of the alloy were analyzed by DSC,XRD,DC and AC soft magnetic testing equipment.The effects of Ni and Co content on the amorphous forming ability and magnetic properties of the boron-rich Fe Si BCu Nb Ni(Co)alloy were explored.The result shows:1)In Fe_79-ySi_18-xB_xCu₁Nb₂Ni_y(x=15,16;y=10,15,20)alloys,the amorphous forming ability of the strip is weak.The Fe₆₈Si₃B₁₆Cu₁Nb₂Ni₁₀ amorphous alloy was prepared by optimizing the composition,indicating that the high total content of(Si+B)can effectively improve the amorphous forming ability of the Fe Si BCu Nb Ni alloy.2)For Fe_78-xSi₃B₁₆Cu₁Nb₂Ni_x(x=10,12,13,14,15)series alloys,as the Ni content increases,the alloy's amorphous forming ability gradually weakens;when the Ni content is 10 at.%?12 at.%,the amorphous strip is successfully prepared.When the Ni content exceeds 12 at.%,Fe Ni₃ crystalline phase is generated inside the alloy.In Fe₆₆Si₃B₁₆Cu₁Nb₂Ni_12-xCo_x(x=2,4,6)series alloys,when the substitution amount of Co element does not exceed 4 at.%,the alloy has strong amorphous forming ability and can prepare amorphous ribbons with a thickness of about 21?m;When the Co content reaches6 at.%,the alloy crystallizes.3)The thermal stability of Fe_78-xSi₃B₁₆Cu₁Nb₂Ni_x(x=10,12)two amorphous alloys is similar,and when the Ni content is 12 at.%,the heat treatment temperature range for forming a single phase of?-Fe(Ni)nanocrystalline is narrow,and the nanocrystalline structure The stability is weaker;In Fe₆₆Si₃B₁₆Cu₁Nb₂Ni_12-xCo_x(x=2,4)amorphous alloy,with the increase of Co content,the thermal stability of the alloy increases,and the heat treatment temperature range for the formation of?-Fe(Ni)nanocrystalline single phase is broadened.Compared with Fe_78-xSi₃B₁₆Cu₁Nb₂Ni_x alloy,Fe₆₆Si₃B₁₆Cu₁Nb₂Ni₁₀Co₂ alloy has lower thermal stability in the amorphous phase,while the thermal stability of the nanocrystalline phase is somewhere in between.4)The coercivity of Fe₆₈Si₃B₁₆Cu₁Nb₂Ni₁₀?Fe₆₆Si₃B₁₆Cu₁Nb₂Ni₁₂and Fe₆₂Si₄B₁₆Cu₁Nb₂Ni₁₅ alloys reaches the minimum value of 6.9 A/m,8.3 A/m and 10.0A/m at 480?,470?and 470?for 10 min,respectively.The hysteresis loops of Fe₆₂Si₄B₁₆Cu₁Nb₂Ni₁₅ alloy annealed at 440?to 500?tend to be flattened and the permeability decreases with the increase of annealing temperature.The Fe₆₈Si₃B₁₆Cu₁Nb₂Ni₁₀ alloy that has undergone ordinary heat treatment at 480?has the lowest loss.When the maximum magnetic induction intensity B_m=100 m T,the loss measured at 10 k Hz and 100 k Hz is 1.0 W/Kg and 23.5 W/Kg,respectively.5)The coercivity of Fe₆₆Si₃B₁₆Cu₁Nb₂Ni₁₀Co₂ alloy first decreases and then increases with the increase of temperature,and the minimum coercivity is 9.7 A/m when annealed at 480?.When the Fe₆₆Si₃B₁₆Cu₁Nb₂Ni₈Co₄ alloy is annealed at 440?for 10min,the coercive force is the lowest at 6.6 A/m.6)In the series of Fe₆₆Si₃B₁₆Cu₁Nb₂Ni_12-xCo_x(x=2,4)alloy,the loss of Fe₆₆Si₃B₁₆Cu₁Nb₂Ni₈Co₄ alloy after common heat treatment is lower.When the maximum magnetic induction intensity B_m=100 m T,the loss measured at 10 k Hz and 100 k Hz is 2.0W/Kg and 47.6 W/Kg,respectively.